来自高嵘的问题
(3a+1)(2a-3)-(4a-5)(a-4)计算
(3a+1)(2a-3)-(4a-5)(a-4)计算


(3a+1)(2a-3)-(4a-5)(a-4)计算
(3a+1)(2a-3)-(4a-5)(a-4)计算
(3a+1)(2a-3)-(4a-5)(a-4)
=6a²+2a-9a-3-(4a²-5a-16a+20)
=6a²-7a-3-4a²+21a-20
=2a²+14a-23